Study on seismic performance of cold-formed thin-walled steel composite walls infilled with fiber gypsum-embedded straw bricks

To reduce the self-weight of infilled cold-formed thin-walled steel composite walls and improve their strength, stiffness and seismic performance, this paper presents a composite wall configuration with embedded straw bricks. Three groups of full-scale specimens were fabricated and subjected to low-cyclic reversed loading tests. The failure modes, hysteretic responses, skeleton curves, ductility, stiffness degradation and energy dissipation capacity were systematically analysed to reveal how structural configurations affect the seismic behaviour of the walls. Test results show that wall failure is mainly characterised by gypsum cracking, while straw bricks suffer negligible damage. The proposed system effectively upgrades the bearing capacity, lateral stiffness and ductility of infilled cold-formed thin-walled steel composite walls. Relative to hollow walls, the bearing capacity increases by 377.5%, lateral stiffness by 34.6%, and the ductility coefficient by 226.8%. The flat steel strip frame alleviates gypsum board damage and exhibits excellent ductility, whose ductility coefficient is 111% higher than hollow walls. In addition, the ductility coefficient of the straw-brick-embedded composite wall is 54.6% greater than that of the flat steel strip light steel frame wall.